When a driver is driving his car, other drivers therebehind may need to know what he intends to do. For example, when the front driver is going to change lanes from a right one to a left one, he needs to turn the steering wheel leftwards to have the car approach the left lane. Meanwhile, the drivers originally at the left lane behind the lane-changing car shall keep their eyes on the turning car to avoid collision. Generally, a left indicator light flashing with orange light is enabled by the front driver to warn the drivers therebehind at this time. Sometimes, however, the front driver may forget to switch on the indicator light so that the approaching of the front car is not obvious or does not hold attention from the rear cars. Many car accidents occur under this circumstance. Therefore, it is preferred that the turning of the car is notified automatically to warn other drivers.
Desirably, a vehicular turning indicator enabled to dynamically show the turning status of a vehicle is provided. By lightening up different numbers of lamps according to different turning degrees, the other drivers of vehicles around the present vehicle and even the driver himself of the present vehicle can clearly understand the moving situation of the vehicle. Therefore, the drivers can well respond to the situation so as to assure of safety on the road.
U.S. Pat. No. 5,673,019 described an automatic turn signal and safety device to solve the problem. As shown in FIG. 1, six lamps L1˜L6 are arranged at the left side of a vehicle and other six lamps R1˜R6 are arranged at the right side. The prior art device comprises a disc 10 sleeved around the steering column 20, three wiper electrodes 11, 12 and 13, three left disc electrodes 14, 15 and 16, and three right disc electrodes 17, 18 and 19. Originally the wiper electrodes 11, 12 and 13 are in the neutral area of the disc as shown when there is no turning operation of the steering wheel. The three left disc electrodes 14, 15 and 16 are electrically connected to the three sets of lamps (L1, L2), (L3, L4) and (L5, L6) via wires W1, W2 and W3, respectively. The three right disc electrodes 17, 18 and 19 are electrically connected to the three sets of lamps (R1, R2), (R3, R4) and (R5, R6) via wires W4, W5 and W6, respectively. When the car is made a slight right turn, it is only the wiper electrode 11 in electric contact with the right disc electrode 17. Accordingly, positive current flows from the electrode 17 to the wire W4 to turn on the lamps R5 and R6. If the car is made further turn to an intermediate level, both of the wiper electrodes 11 and 12 are in contact with respective right disc electrodes 17 and 18. Accordingly, two sets of lamps (R5, R6) and (R3, R4) are turned on. Likewise, an even large turning degree turns all the six right lamps R1˜R6 on.
Similar operations are applicable to the left turning signals. When the car is made a slight left turn, it is only the wiper electrode 11 in electric contact with the left disc electrode 14. Accordingly, positive current flows from the electrode 14 to the wire W1 to turn on the lamps L5 and L6. If the car is made further turn to an intermediate level, both of the wiper electrodes 11 and 12 are in contact with respective left disc electrodes 14 and 15. Accordingly, two sets of lamps (L5, L6) and (L3, L4) are turned on. Likewise, an even large turning degree turns all the six left lamps L1˜L6 on. Therefore, by flashing different numbers of lamps, the rear drivers can understand how the front car is moving. Since the lamps are arranged in the front of or in the rear of the vehicle, the driver himself cannot see the change of the lamps.
Although the prior art device as shown in FIG. 1 is capable of warning other drivers of the turning operation, the circuitry is complicated and the effect is limited. For example, three lamps only at each side are difficult to hold attention from other drivers unless the lamps are large enough. The large size of the lamps, however, occupies too much space of the vehicle body and may have bad effect on the look of the vehicle. Moreover, the turning degree can only be roughly expressed by the three lamps at each side. If more lamps are used, the above-mentioned problems are even serious. In addition, more wiper electrodes, disc electrodes and connecting wires are needed to optionally turn the lamps on.
On the other hand, when the speed of the car is fast, a much more prominent turn signal is required to notify the rear drivers. The above-mentioned prior art, however, does not take this effect into consideration.